Why doesn't this formula seem to work with convex mirrors? or did i miss somthing?

Hello everyone, I seem to be getting all the mirrors right that where concave but now i have a convex one and it doesn't seem to be working when im' finding the image distance and magnification/properties.

Here is the problem:

Object O stands on the central axis of a spherical mirror. The table gives object distance p, the type of mirror, and focal distance f. Find the image distance i and the lateral magnification m of the object, including signs.

First off, you haven't drawn a picture! Ray diagrams are very useful in these types of problems. The tricky part of lenses is making sure that all your signs are correct. For this type of mirror, I believe the focal length is negative. Do you understand what the difference is between a real and a virtual image? Do you understand what is meant by the focal length? The diagram will be helpful. Draw a convex mirror with an object in front, then draw the light-rays coming off the object and see where they go after bouncing off the mirror. Plugging and chugging won't help you understand the concepts, and a good understanding of the concepts is the key to tricky test questions.